Apparatus for the diagnosis and the control of treatment of diseases of the eye



June 2, 1953 I w. v. s'rEPHENsoN APPARATUS ROR THE DIAONOsIs ANO THECONTROL OE TREATMENT OF DIsEAsEs OF THE EYE Filed .July 9, 1952 \.l// J.0 \V\ om ev 0 0 78 2 m. 3 I l f ll L 3 2 .I f/// /f/n//H/ M E lcd vo l/f/ M M u .H 7 H/e: .M l/ 9 l e l ///V///// l W W A f L 3 2 3 i 2 //l l4 K f 2 DI- 7. 223 I 0 .I Il L 3 2 /r UV. I 2 a DW I I .I I I.

2 L 5 L x 3 N 5 w .M 9) l a 1 I .l A 3 2 m am M 4 a, a 2 mw l 3 lPatented. June 2, 1953 APPARATUS FOR THE DIAGNOSIS AND THE CONTROL OFTREATMENT OF DISEASES OF THE EYE William V. Stephenson, Toledo, OhioApplication July 9, 1952, Serial No. 297,834

Claims.

This invention relates to a method for diagnosing and controlling thetreatment of diseases of the eye and to apparatus for carrying out ofthe method of the invention.

It is, of course, well known that tissue injury, such as thataccompanying infection, or other injury, is always accompanied by therelease of histamine from the tissue cells which causes a localdilatation of the minute blood vessels, a local increase in thepermeability of the capillary walls and a dilatation of the neighboringarterioles resulting from local nerve reflex. All of these result in anincrease of blood to the injured area frequently apparent as aninammation, a swelling, or similar indication. These manifestations ofinjury are accompanied by resulting changes in temperature of thetissues affected.

It is also known that the temperature of the eye at any time results notonly from its pathological condition but from any variants such as theambient temperature, rate of flow of tears, humidity of the surroundingair and thus the evaporation of the tears, and the blink rate.

The concept of the instant invention thus includes not only therealization that comparisons between the temperatures of the eyes areindicative of the condition of the eyes and that the change in thetemperature of an eye over a period of time is indicative of theimproving or deteriorating condition of that eye but also the concept ofapparatus by means of which such `temperatures can be accuratelymeasured.

It is, therefore, the principal object of this invention to provide amethod by means of which accurate diagnosis of the presence of diseasein .I'

the eye can be achieved.

It is another object of this invention to provide a method for the rapiddetermination of the efficacy of an adopted treatment for a diseasedeye.

In the past a physician was forced to depend upon visible indications ofthe effectiveness of the treatment technique adopted, for example,injections of a selected antibiotic, and frequently aseveral day periodhad to elapse before sumcient change in the visible condition of the eyetook place for the physician to determine whether or not the treatmentwas effective. Unfortunately, in instances where the wrong technique hadbeen adopted, the disease might have progressed alarmingly before thephysician had any reason or any indication to change the method oftreatment. In contrast, through the practice of the instant invention,indications of the effectiveness of the treatment technique are`available within a matter of relatively few hours.

A CII It is another important and concurrent objective of this inventionto provide apparatus embodying its fundamental concept, i. e., that thetemperature of the available surface of the eye, the cornea and exposedportion of the sclera accurately reflect the physiological condition ofthe eye and can be depended upon as an accurate indication of therelative condition of either eye over a period of time and of thecomparative conditions of the two eyes at any time and through a periodof treatment.

As mentioned, the discovery that the temperature of the cornea and/orthe sclera is highly indicative of the condition of the eye has madefeasible the invention of the apparatus and treatment and diagnosticmethod embodying the invention. Were the temperatures of these two areasof the eye surface not indicative, measurementof the temperature ofother portions of the eye would require techniques such as surgery orasimilar violent treatment which, in themselves, might affect thetemperatures being measured.

The procedures and apparatus embodying the inventiony which are setforth in the specification that follows may be more fully understood byreference to the drawings attached hereto, in

which: j

Fig. 1 is a schematic showing, with portions of the useful apparatusshown in section, and including aschematic wiring diagram of apparatusembodying the invention as assembled for the carrying out of the methodof the invention.

j Fig. 2.is a greatly enlarged fragmentary view illustrating theportions of the apparatus actually directly applied to the cornea of theeye the .temperature of which is beingmeasured.

Fig. 3 isa fragmentary view of a modification of the eye contactingportion of the device.

In describing the clinical technique involved in the practice of theinstant invention and in illustrating and describing apparatus embodyingthe invention, techniques and apparatus for measuringcorneal temperaturewill be explained but the invention is not limited to measuring thetemperature of the cornea and the same techniques and apparatus areeffective also for measuring the temperature of the exposed portion ofthe sclera.

In carrying out the method of the invention it is important to eliminateinsofar as'possible all errors or possibility of errors due to the manyfactors known to iniiuence eye temperatures. It has been determined, forexample, that local anaesthesia brings about practically completevasodilatation of the peripheral blood vessels thus causing a rise intemperature of the area. The

'A inuence of4 anaesthesia on the temperatures of the eye being measuredmustl be compensated for by the employment of identical anaesthetizingtechniques in each measurement. For example in the ypractice of theinstant invention, the effect may be standardized by the instillation ineach case of one drop of, for example, 0.5% Pontocaine at the same placein each eye. for example, at 12 oclock" on the limbus. The patients lidsmay then be left closed for a period of one minute to permit absorptionof the anaes-thetic.

In order to eliminate any error which might I result from unnaturalblink reflex, the eyes are then opened and, for a period of ve minutes,al-

lowed to readjlust themselves to reestablish the normal blink frequency.Y

The rates of evaporation of the eye fluids and of the anaesthetic andthe eiect of ambient temperature vand air humidity on the eyetemperatures are controlled by carefully regulating both the temperatureand humidity of the air in the 'room where the measurements are taken.The effect of outdoor temperatures and humidity on the eyes of thepatient are standardized by placing the .patient in a treatment roomwith controlled temperature and humidity for a suflicient period' priorto the tests for the eyes to respond to the room temperature.

Thus by the careful control of surrounding conditions so as tostandardize their eiect upon the corneal temperatures of the patientsbeing treated, these sources of error while not eliminated, arestandardized so that comparative temperatures `taken at different timesare based upon the same conditions surrounding the patient.

Because rof the high degree of accuracy necessary in the measurementstaken, it is important that the eiect of al1 parasitic electro-motiveforces should be eliminated as nearly as possible from the measuringapparatus. This is accomplished by insulating the various components Ielectrically and thermally. Again, because of the small temperaturechanges being measured it ris necessary that the measuring components ofthe apparatus employed should be isolated insofar as possible 'from theeffects of vibration and ambient air temperatures and currents. Themeans for accomplishing these steps of protection of the apparatus willbe set forth in the I'description of the apparatus that follows:

A measuring :apparatus embodying the invention comprises, among otherparts,'a receiver, generally indicated lby the reference character I 0.and consisting in a circular (Figs. 1 and 3) cr 'partially spherical(Fig. 2) plate II or Ila and conducting wires I2 and I3. The plate IImay beabricated from gold foil, for example, 1 millimeter in diameterand microns thick. The two wir-es I2 and I3 may be wire gauge number li0(approximately the thickness of a human hair) and made from thermallyresponsive alloys, kfor example, those called Alumel and Chromelrespectively. The two Alumel and Chromel wires `I2 and I3 Iare welded tothe gold leaf receiver plate Il.

In the original experiments the receiver plate lla (Fig. 2) was soshaped that it could be held in contact with the cornea by surfacetension of the tear liquid. LAt a later date it was discovered that anintimate contact of this kind was not. necessary and the receiver plateI I (Figs. l and 3) was made iiat so that physical contact. only, wasmade between the receiver plate and` the cornea of the eye. This reducedthe small irritation of the application of the receiver to the corneaand simplified the measurement.

Therefore the receiver plate can be made in either `curved or plane formwith satisfactory results.

The receiver element I comprising the contact plate I I and two leadwires I2 and I3 is mounted by means of a thin glass tube |'4 from theopen end of which short lengths of the two wires protrude. The glasstube Ill thus serves vas a handle by means of which the contact plate II can be placed against the cornea and also as an insulator to preventthe temperature of the hand of the physician from innuencng thetemperature of the eye being measured.

The glass tube I4 is inserted in the open end of a exible plastic tubeI5 through which the two lead wires I2 and |3 are led to a thermallyinsulated container |6. VThe plastic tube l5 is fitted over a shortgla-ss tube I'I which may, for example, lbe inserted in a stopper IB4for closing the upper end of the container IB. In the interior of thecontainer I6 the two lead wires I2 and I3, for example, .Alumel andChromel or iron and constantan respectively, are electrically connectedto other lead wires I9 and 2G. The wire 20 is one of a ypair of leadwires 20 and 2| which, in this instance, also are Alumel and Chromelrespectively, so that the Alumel lead wire I2 is connected to the Alumellead wire 20. The Chromel lead wi-re 2| is connected to ya conductor 22which is paired with the yconductor I9 and led out of the container I6,for example, through a glass tube 23 in a stopper 24. The two conductorsI3 and 22 can be fabricated from fine copper or other conductingmaterial and electrically insulated only (electrical insulation is notshown in the drawings) The two thermocouple Wires 20 and 2| are led outof the insulated container I6 through a second glass tube 25 in thestopper I8 and through a protective plastic tube 2t in the end of whichthe glass tube 25 is inserted and then through a glass tube 21 overwhich the other end of the. plastic tube 2E is `fed. The glass tube 2len-ters a thermally insulated liquid containing iiask 28 through itsstopper 29. The flask 2.8 is enclosed in a mass lof Thermal insulationcontained in an enclosure 30. y The two thermocouple wires 20 and 2| arejoined as at 3| inside the ilask 28 and beneath the surface of aconstant temperature bath 32 maintained therein.

The bath 32 is maintained in the ilask 28 for the purpose ofestablishing a constant reference temperature for the thermocouplejunction at 3|. This bath, for example, may consist in a saturatedsolution of sodium sulfate decahydrate crystals (Glaubers sa1ts) andsodium sulfate anhydrous in the well known constant temperaturerelationship. This bath is particularly good because it exists at thetemperature of 32.383 C., which is quite close to a general average ofthe corneal temperatures. Thus the deilections in any measuringinstrument will be relatively small.

The conducting wires I9 and 22 are led to an instrument box 33containing an ultra sensitive galvanometer 34 which should be responsiveto very small changes in E. M. F. resulting from small changes intemperature at the measuring thermocouple on the cornea. For example,the galvanometer may be of the type having a sensitivity of, say, .05microvolt per millimeter.

The lead I9 isconnected to one side of a normally open switch 35 and thelead 22 connected to a junction 36. The other side of the switch 35 isconnected. by a lead 3l to a junction 38.

The junctions 36 and 38 are connected by a lead 39 in series witharesistance 40. The galvanometer 34 `is, connected to the junctions 36and 38 in parallel with a switch 4I,resistance 42 and cell 43 that areconnected together in series to the junctions 36 and 38.

The cell selected should beconstant in E. M. F. and in practice it hasbeen found that a mercury cadmium amalgam cell of the unsaturated typehaving a E. M. F. of slightly more than 1 volt is effective.

Although the gold leaf contact disk Ila, constructed as shown in Fig. 2,is effective in detecting small changes in temperature, earlyexperimentation showed that it was too fragile vrnechanically to permitsterilization.V In further experiments using the apparatus embodying theinvention, the gold` leaf was replaced by a platinum disk (as shown inFigs. 1 and 3)A approxi-v mately 2 millimeters square and 0.0006millimeter thick. Experiments have shown that platinum, as a materialfor the construction of the disk I I, is no more irritating to thecornea of the eye than gold foil and its greater strength due to itsthickness and size facilitates handling the apparatus duringexaminations and experiments. Success also has been achieved using areceiver made of gold .008 cc. thick and approximately 6 mm. indiameter, these dimensions and the others being merely illustrative.

Because of the very small electromotive forces to be measured, it isessential that all source of error should be eliminated from theelectrical circuit itself. For this reason the circuit includes the cell43 and switch 4I arranged in parallel to the leads from the thermocouplecorneal temperature measuring portions of the device. When the switch 4Iis closed a known E. M. F. from the cell 43 is applied across thegalvanometer. This checks the accuracy of the galvanometer andestablishes any constant deflection due to galvanometer lag which cansubsequently be balanced off in the recording of temperatures. Thesecond step in eliminating errors due to the electrical nature of theapparatus consists in immersing the corneal temperature receiver, i. e.,the thermocouple junction consisting in the ends of the wires I2 and I3and the plate I I, in the constant temperature bath 32 with thethermocouple junction at 3|. There is, therefore, no difference intemperature between the two thermocouple junctions and the deflection ofthe galvanometer thus is directly established by the known temperatureof the bath 32 and the resistance of the electrical elements in thecircuit. This deflection is compared with the deflection of thegalvanometer under the known E. M. F. from the cell 43. It is thenpossible to calculate a constant K for the apparatus, according to theequation In this equation t equals the temperature of the cornealcontacting thermocouple junction at the plate I I, K the constant forthe apparatus, d2 the deflection of the galvanometer with both junctionsin the constant temperature bath and d1 the deflection of thegalvanometer when connected to the cell 43.

With the reference junction at 3I maintained at a constant temperaturein the bath 32 and knowing the constant K established for the apparatusas above, the scale on the galvanometer 34 can be so adjusted andestablished that galvanometer deflections d2 are directly proportionalto, and can be directly indicated as, temperatures at the cornealcontacting junction on the plate I I. The procedure for taking thetemperature of an eye to be vtested consists in first accommodating thepatient to the temperature and humidity of the examination room in orderto eliminate the effect of temperature and humidity elsewhere on thetemperature of the particular patients eyes. 'The two eyes are thenanaesthetized by the application of a carefully measured amount ofanaesthetic appliedto a particular point in each eye, for example asmentioned above 1 drop of 0.5% Pontocaine The patients eyes are thenmaintained closed for a period of 1 minute and rested open for 5 minutesto reestablish the normal blink period. The measuring thermocouplejunction comprising the plate Il is then placed against one of thepatients eyes and the temperature recorded. As quickly as possible it isthen placed against the other of the patients eyes and that temperatureis recorded.

By many experiments it has been determined that the average cornealtemperature for most people is 33.6 C. If both of the eyes arereasonably close to this average it is probable that neither of the eyesis diseased but the two eyes will not have the same temperature in themajority of cases. Experimentation and testing have revealed that thetemperatures of two normal eyes are likely to vary as much as .1 C.

If the temperature of one eye is found to be higher than that of theother by an amount substantially greater than .1 C., for example, but aslittle as .5 C. or less, or as much as 4 or 5 C., it is a conclusiveindication that that one of the eyes having the higher temperature isdiseased. Where a substantial temperature difference between the twoeyes is thus detected, the physician is able to immediately diagnose adiseased condition even if other manifestations of disease such asinflammation or swelling or high tear flow, etc., are not yet present.

The physician then makes additional examinations, tests and studies ofthe wual nature in an attempt to positively identify the nature andcause of the diculty and may reach-a conclusion based upon his knowledgeof the subject matter as to the particular disease from which thepatient is suffering. Experimentation has. indeed, indicated that thedegree of difference between the temperatures of the two eyes is initself indicative of the nature of the difliculty in the diseased eyeand a large variation can be interpreted as resulting from a causedierent from that which produces a much smaller variation.

In any event the physician thendetermines upon a method of treatment,for example, he may inject a selected antibiotic into the patients bloodstream. Surprisingly, in as little as 24 hours time, if the medicationor treatment is proper for the disease present, the temperature of thewarmer eye will drop appreciably. Under these conditions continuedtreatment over subsequent days will be reflected in a continuing drop intem- I perature. When the temperature of the diseased eye approachesthat of the normal eye, the physician can determine that a'cure isalmost effected even though other manifestations of the diseasedcondition may have disappeared long bel fore the temperature of the eyehas approached normal (the temperature of the unaffected eye plus orminus, for example, .1 C., depending upon the individual).

If, on the othelf bend, the diiferential between ations? the'temperatures of the two eyes has remained the same or has increasedwithin the first 24 hours after selected treatment, it is conclusivethat the method of treatment chosen wasin'- appropriate for the diseasepresent. The physician thus is given early Warning that his treat mentis not eiective and he can change treatment before a suiiicient timepasses for the eye to have been much more seriously injured by thedisease.

In the event that both eyes are diseased at the time of the originalmeasurement, the physicians attention to the condition will beestablished by reason of an appreciable difference in eye terri-Vperature alcove the normal of 33.6 C. and prob- Case A white femalepatient, age 44, and apparently in normal health, had complained ofblurred vision in the left eye for several weeks. Several competentOphthalmologists had examined the eye by routine medical examinationmeans and found no indications of disease, in fact, had found the eyeentirely normal. first day the right eye was found 20/20 and the lefteye 20/30. The patients corneal temperatures were taken by use ofapparatus embodying the invention and in accordance with the methodoutlined above the following temperatures were indicated: right cornealtemperature 33.4 C., left corneal temperature 33.9 C. While these twotemperatures were reasonably close to the average temperature of 33.6C., the dilference of .5 C. between the tWo eyes indicated disease inthe left eye. The patient, therefore, was given a complete and thoroughphysical examination, in-l cluding blood chemistry, urinalysis,tubercular skin tests, teeth and chest Xrays, mass agglutination andhead X-rays. X-rays of the sinus areas revealed a slight clouding of thefrontal, ethrnoid, and inaxillary sinuses. From these indications thepatient was placed on a treatment of chloramphenicol (antibiotic),triple sulfon amides, foreign proteins and ephedrine nasal packs.

Under normal conditions of treatment without tneuse of apparatus andmethods embodyingr the invention, a period of several days would thenhave had to elapse before detectable response to the treatment wasapparent. Indeed, three days later the vision in the diseased eye haddropped to 10/200 and there was one diopter of papilloedema. Theseresults would appear to indicate that the treatment adopted was notcorrect. Examination through the use of apparatus of the invention,however, revealed that the temperature of the diseased eye had startedto drop and the difference between the temperatures of the eye wasconsiderably smaller. Shortly thereafter the eye began to clear, provingthat the treatment continued as indicated by the measured reduction indifference between the temperaturesl of the normal and diseased eye waseffective. On the eleventh day after first examination the cornealtemperature of the left eye had dropped to 32.3

By vision tests on the 8 C. and the right eye had dropped to 31.9%?.This' substantial reduction in the temperature of each eye indicatedreduction in the 'general diseased condition and showed a difference ofonly .4 C. between the two eyes. Bythe twentieth day after treatment thevision in the tW'o eyes had `re-i turned'to the original right 20/20 andleft 20/30. The difference between the corneal temperatures had' droppedto .3 C. All medication except the foreign protein was discontinued andby sixty days after treatment commenced the tempera. tures of the twoeyes diirered by only .07 C., indicating a complete cure. All therapywas then discontinued.

The advantages accruingV from the use of the apparatus embodying theinvention in the case detailed above were two. First, in the face ofseveral examinations none of which revealed any abnormality in the eyes,the original difference of..5 C. Was sufficient to require extensiveexaminations not normally resorted to to determine any diseasedcondition. Second, in the face of an apparent complete cureV as of thetime when the vision had returned to normal, therapy was continuedbecause of the still substantial differeence in temperatures of the twovcorneas until complete cure was effected sixty days after firstexamination.

Caso II An even more forceful illustration of the effec# tiveness of themethod of the apparatus in detect-` ing and controlling disease of theeye appears in the case of a white female, age 52, who was firstexamined and found to have corneal temperatures in the right eye of 35.4C. and the left eye 31.1. This diiference of 4.3" C. indicated a verysevere infection. At the same time the vision in the eyes was right eye20/200, left eye 2li/2i). Treatment was started at once. By the fourthday the temperature in the affected eye vhad dropped appreciably, thedifference between the two eyes being only .7 C. By approximately thefiftieth day after treatment commenced, the vision in the tWo eyes wasmeasured at right eye U20/50 and left eye 20/20. The eyes a'ppeaired4 tobe clear and normal and the pain had completely disappeared. Undernormal conditions all treat-A ment probably would have been stopped atthis time, but through the use of apparatus embody' ing the invention itwas' found that the difference in corneal temperatures was still .4.3sC., which was too great for normalcy. Intensive treatment, therefore,was continued for an ,additional .period of fifteen days. At the end ofthat time the core heal temperature difference had dropped to .O26i C.and upon `exarriination vision was right eye 20/40 and left 'ye- 20/'20.

Apparatus embodying the invention, including' the concept of diagnosisand indication of treat-k ment effectiveness through the use thereof,for the measurement of corneal temperatures com stitutes the subjectmatter of the present invention which is set forth in' thesubjoinedclaiins'.

I claim: i,

l. Apparatus for determining the pathological condition of an eyecon'fiprsi'ng,` in combination, a galvanometer; a therr'noccuipleconnected thereto, said thermocouple having one junction consisting in asmall thin metallic plate adapted to be contacted to the normally`exposed surface of an eye `under examination anda pairof diifer.

ent thermally responsive conductors mechanically secui'ed adjacent eachother to said plate, and a second junction of a second .pair of siini-ylar conductors; a vessel for maintainingfa cori- 2' stant temperaturebath in which said second junction is maintained; a thermally insulatedbox into which the non-junction ends of both of said ipairs ofconductors are maintained, a like one of each of said pairs ofconductors being electrically connected; and electrical leads from theother like ones of each of said pairs of conductors to saidgalvanometer.

2. Apparatus according to claim 1 having a source of known E. M. F.electrically connected in parallel with said thermocouple leads andswitching means for alternatively connecting said source of known E. M.F. and said thermocouple to said galvanometer.

3. In a thermocouple actuated temperature measuring apparatus having agalvanometer for indicating the thermocouple potential, the improvementsconsisting of a second thermocouple constructed from two materialsidentical to those of the rst said thermocouple, means for maintainingthe junction of said second thermocouple at a constant referencetemperature, the junctions of said first and second thermocouples havingone pair of like Wires connected to each other and the other pair oflike wires in series with lead wires to said galvanometer, and athermally insulated enclosure for the connections between the rst saidpair of like wires and the connections between the other of said pairsof like wires and said lead Wires,

4. Apparatus for measuring the corneal temperature of an eye of apatient comprising, in combination, a sensitive galvanometer, a sourceof known E. M. F., a double thermocouple having two junctions, eachthermocoulple having a junction consisting in electrically connectedends of two wires of diierent thermally responsive resistance, one ofsaid junctions being a reference junction, the other of said junctionsincluding a corneal contact disk mechanically and electrically connectedto the ends of said wires, means for maintaining said reference junctionat a constant temperature, a thermally insulated connection box,Agalvanometer leads into said connection box, the non-junction ends ofone pair of like wires of said thermocouples being electricallyconnected and the similar ends of the other pair of like wires beingconnected in series with said galvanometer leads, such connections beinglocated in said connection box and electrical means for alternativelyconnecting said source of known E. M. F. and said thermocouples inseries with said galvanometer.

5. Apparatus for measuring the temperature of the normally availablesurface of an eye of a patient comprising, in combination, a sensitivegalvanometer, a, source of known E. M. F., a double thermocouple havingtwo junctions, each therm'ocouple having a junction consisting inelectrically connected ends of twowires of different thermallyresponsive resistance, one of said junctions being a reference junction,the other of said junctions including a surface contact diskmechanically and electrically connected to the ends of said wires, meansfor maintaining said reference junction at a constant temperature, athermally insulated connection box, galvanometer leads into saidconnection box, the non-junction ends of one pair of like Wires of saidthermocouples being electrically connected and the similar ends of theother pair of like wires being connected in series with saidgalvanometer leads, such connections being located in said connectionbox and electrical means for alternatively connecting said source ofknown E. M. F. and said thermocouples in series with said galvanometer.

WILLIAM V. STEPHENSON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,942,516 Noyes Jan. 9, 1934 2,025,534 Sheard et al Dec. 24,1935

